Development And Performance Evaluation Of A Tray Column Under Vertical And Tilt Conditions

ABSTRACT

In this work, the operation and performance of a novel Separation Tray Column under Vertical and Tilt conditions is presented. The Tray Column used for the work is a Downcomerless liquid initiated and controlled Valve Tray with capacity to shut portions of the tray lacking liquid at any time. To evaluate the mass transfer performance of this column, an oxidation experiment was conducted at 300C and the percentage of Fe (II) oxidised to Fe (III) from contaminated water by air was chosen as the system response. The influence of the Gas flowrate (x1 in litres per minute), the Liquid flowrate(x2 in litres per minute) and the Angle of tilt (x3 in degrees) on the response was represented by polynomial models and their effects were studied using the Student’s t-test and Fischer’s F-test for the Analysis of Variance (ANOVA) for each model. Out of the 5 models, the experimental data were found to be best represented by a linear polynomial model with Coefficient of Determination R2 = 0.9635. The test of significance of the individual coefficients in the model based on the Student’s t-test showed that only parameters x1 and x2 (i.e. the gas and liquid flowrates) are significant at 95% confidence level. The angle of tilt (with p=0.18) had no significant influence on the amount of Iron (II) oxidised. The ANOVA of this model showed that the model was significant as the calculated F-value (F-model = 17.60) exceeded the tabulated F-value (6.16), and also from its probability value (p=0.008) which is less than 0.05. From this test also, the model parameters x1 and x2 had significant influence as their calculated F-values (164.57 and 45.38 respectively) were much higher than their tabulated F-values (F=7.71). The parameter x3 and their interaction effects were still not significant from this test as their calculated F-values (5.42 for x3, 0.06 for x1x3 and 0.2 for x2x3) are less than their tabulated F-values of 7.71. These findings were further validated by the x-y scatter plots which showed that for all the liquid flowrates, the % Fe (II) oxidised increased with increasing vapour flowrates but the impact of the angles of tilt was minimal. The implication of these is that the operational efficiency of this novel tray column will not be compromised by column tilt of up to 20 degrees from the vertical.